Android 6.0 Marshmallow, thoroughly reviewed | Ars Technica After a lengthy developer preview, the newest version of Google's flagship operating system is finally ready for the masses. Android 6.0 Marshmallow is the twenty-third version of Google's "mobile" operating system, though it can accurately be described as "mobile" only if you're referring to how much it gets around. With all the areas in which Google now tinkers, Marshmallow is destined for smartphones, tablets, watches, televisions, and cars, among others.